Augmenter fuel injection mounting system

ABSTRACT

An augmenter fuel distribution system for a gas turbine engine includes a fuel manifold assembly mounted externally of the engine casing, a plurality of fuel injection spraybar bundles, a metering valve housing associated with one or more of the spraybar bundles, each housing including a mounting pad for mounting the housing and spraybar bundle directly to the fuel manifold assembly, thereby supporting the bundle in the radial direction, a seal and damper assembly which mounts to the casing and supports the bundle in the axial direction while permitting relative thermal expansion between the bundle and the casing.

I Unlted States Patent 1 [111 3,793,838

Nash 1 1 Feb. 26, 1974 1 AUGMENTER FUEL INJECTION 3,181,297 5/1965 Belket al 60/39.74 x MOUNTING SYSTEM 3,572,733 3/1971 Howald et al.. 285/158X 2,969,925 1/1961 Burgess et a1 (SO/39.74 R

[75] Inventor: Dudley O. Nash, Forest Park, Ohio [73] Assignee: GeneralElectrical Company,

Cincinnati, Ohio [22] Filed: Sept. 5, 1972 [21] Appl. No.: 286,434

[52] US. Cl 60/261, 60/39.32, 60/39.74 R [51] Int. Cl F02c 3/04, F02c7/22 [58] Field of Search 60/39.74 R, 261, 39.32;

[56] References Cited UNITED STATES PATENTS 3,147,594 9/1964 Hill et al.60/39.74 R 2,978,870 4/1961 Vdoviak 60/39.74 R

2,523,741 9/1950 Weschler et al. 248/56 3,565,445 2/1971 Hodges 277/187X 3,514,954 6/1970 Colley 60/261 3,335,567 8/1967 Hemsworth 60/39.743,698,186 10/1972 Beane et al. 60/261 X Primary Examiner-Carlton R.Croyle Assistant Examiner-Robert E. Garrett Attorney, Agent, orFirmThomas .1. Bird, Jr.; Derek P. Lawrence 5 7] ABSTRACT An augmenterfuel distribution system for a gas turbine engine includes a fuelmanifold assembly mounted externally of the engine casing, a pluralityof fuel injection spraybar bundles, a metering valve housing associatedwith one or more of the spraybar bundles, each housing including amounting pad for mounting the housing and spraybar bundle directly tothe fuel manifold assembly, thereby supporting the bundle in the radialdirection, a seal and damper assembly which mounts to the casing andsupports the bundle in the axial direction while permitting relativethermal expansion between the bundle and the casing.

15 Claims, 11 Drawing Figures AUGMENTER FUEL INJECTION MOUNTING SYSTEMBACKGROUND OF THE INVENTION This invention relates primarily toimprovements in fuel delivery systems for gas turbine engine augmentersand, in particular, to an improved fuel injection spraybar assembly andmounting system.

The invention herein described was made in the course of or under acontract, or a subcontract thereunder, with the United States Departmentof the Air Force.

The present invention may be best understood by referring to itsmotivating environment, namely, gas turbine engines which are widelyused in the propulsion of aircraft. Such engines basically comprise anaxial flow compressor which compresses air'for combustion with fuel inan annular combustor. The products of combustion initially drive aturbine that powers the axial flow compressor and are then directedthrough a discharge nozzle to obtain a propulsive jet force. In certainapplications, additional fuel is injected into the discharge nozzle bymeans of an augmenter or afterburner system. In these cases, theadditional fuel is ignited within the engine exhaust duct and isdischarged through the nozzle to provide additional propulsive force.

In all such augmented engines, the amount of fuel delivered by theaugmenter fuel system must be closely controlled in order to achievehigh performance in the augmenter system. Likewise, it is important thatthe fuel be uniformly introduced around the circumference of the enginein order that substantially uniform combustion exists in the augmenter.Previous attempts at providing uniform and accurately controlled fuelinjection have resulted in the use of injector metering valves which areassociated with each fuel injector point. In addition, the number offuel injection points has been continually increasing in order toprovide uniform combustion throughout the augmenter. On recent enginesas many as sixty injection stations or points have been utilized with asmany as one hundred metering valves associated with the injectionpoints. These metering valves, of necessity, add both cost and weight tothe augmenter assembly and, therefore, a means is needed to achieve highperformance fuel distribution without excessive metering valve weightand cost penalties.

Many present day engines are of the turbofan type in which a fan ispositioned within the inlet of the engine and is driven by a fan turbinewhich forms part of a core engine. The airflow entering the inlet ispressurized by rotation of the fan and is then split into a core engineflow path and a bypass or fan flow path which surrounds the core engineflow path. Complications occur when an augmenter system is added to sucha turbofan engine, especially when augmentation is desired in both thecore engine flow path and the fan flow path. In many such applications,fuel is introduced separately to the fan air stream and to the core airstream and, therefore, separate controls are needed for providing thedesired fuel to both the fan air stream and the core air stream. Anypractical augmenter fuel injection mounting system must, therefore, beadaptable for use in systems wherein separately controlled augmenterfuel is provided to the fan and core engine flow paths.

Common practice in the industry in the past has been to provide flexibletubes (pigtails) between each fuel injector point and a fuel manifoldwhich surrounds the engine casing. These pigtails are provided tosubstantially reduce thermal and vibratory stresses in the high pressuretubing during operation of the engine. Unfortunately, while successfulin reducing thermal and vibratory stresses, the pigtails also addunnecessary weight and increase the overall size or envelope of theaugmenter system. Similarly, the pigtails'require a significant amountof time for removal and replacement should a fuel injection pointmalfunction. Therefore, an augmenter fuel injection mounting system isrequired which eliminates the need for the pigtail tubes.

SUMMARY OF THE INVENTION I It is an object of this invention, therefore,to'provide a mounting system for an augmenter fuel injector whichpermits accurately controlled and uniformly distributed fuel injectionto both the fan and core engine flow paths without the use of pigtailfuel distribution tubes. It is a further object of this invention toprovide such a mounting system which permits quick and easy replacementof individual fuel injectors.

Briefly stated, the above and similarly related objects are attained byproviding a gas turbine engine augmenter fuel injection system in whichfuel injectors are mounted in thermal expansion accommodating fittings,which support the injectors axially 'butpermit radial thermal expansionbetween the exhaust duct and the fuel injector/manifold assembly. Eachfuel injector is provided with a metering valve housing,'which carries aflow metering valveand which mounts directly to a fuel manifoldsurrounding the exhaust duct. Vibration damping is incorporated intoeach-injector mount'fitting such that coulomb damping is provided by atight fitting bushing and bothgas sealing and viscoelastic damping isprovided by a heat resistant elastomer seal. The fuel manifold mayinclude separate piping for the core engine and fan flow paths. Inaddition, provisions are made for mounting twin'fuel injectors at-eachseparate metering valve housing mounting point which permits one set ofmetering valves to service two fuel injection stations.

DESCRIPTION OF THE DRAWINGS While the specification concludes with aseries of claims which particularly point out and distinctly claim thesubject matter which Applicant regards to 'be'his invention, theinvention will be clearly understood from the following detaileddescription, which is given in connection with the accompanyingdrawings, in which:

'FIG. 1 is a schematic, longitudinal section of a gas turbine engineembodying the present invention;

FIG. 2 is an enlarged, fragmentary, longitudinal section of a portion ofFIG. 1;

FIG. 3 is a top plan view, taken generally along-line 3-3, of FIG. 2;

FIG. 4 is a sectional view, similar to FIG. 2, taken generally alongline '44'of FIG. 3',

FIG. 5 is an enlarged, cross-sectional view of the flexible seal, withthe fuel'injector tube removed for clarity;

FIGJSv is a partial, sectional view taken along line6-6 of FIG. 3;

FIG. 7 is a partial, sectional view of an alternative manifold mountingsystem;

FIG. 8 is an enlarged, fragmentary, longitudinal section of analternative embodiment;

FIG. 9 is a top plan view taken generally along line 99 of FIG. 8;

FIG. 10 is an enlarged, fragmentary, longitudinal section of anotheralternative embodiment; and

FIG. 11 is a top plan view taken generally along line 11-11 of FIG. 10.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawingswherein like numerals correspond to like elements throughout, attentionis directed initially to FIG. 1 wherein a gas turbine engine 10 is shownschematically in order to properly set the motivating environment forApplicants invention. The gas turbine engine 10 is of the turbofan typeand includes a core engine 12 which includes a fan turbine 14 whichdrives a plurality of fan blades 16 mounted on a shaft 15. The fanblades 16 are located within an inlet 17 formed by an outer or fancasing 18 which surrounds the entire gas turbine engine 10. The fancasing 18 cooperates with a core engine casing 20 to define parallelflow paths 22 and 23.

Air entering the flow path 23 is compressed by means of a compressor 24and is mixed with fuel in combustor 26. Fuel is delivered to thecombustor 26 by means of a plurality of fuel injection points 27 fromfuel tubes 28 which extend through the flow path 22. The resultant highenergy gas exits the combustor 26 and drives a turbine 30 which, inturn, drives the compressor 24.

As further shown in FIG. 1, air flowing through the outer or fan flowpath 22 and air exiting the core engine 12 is acted upon by an augmenter32, which consists of a plurality of core engine fuel injectors 34 and aplurality of fan injectors 36. The resultant fuel/air mixture in theaugmenter 32 is ignited by means of a suitable igniter (not shown) andthereafter provides an additional propulsive force by exiting through anexhaust nozzle 38.

The gas turbine engine 10 described above is typical of many present dayaugmented turbofan engines and has been described solely to place thepresent invention in proper perspective. As will be clear to thoseskilled in the art, the present invention will be applicable to othertypes of gas turbine engines and, therefore, the engine 10 is merelymeant to be illustrative.

Referring now to FIGS. 2 through 4, the gas turbine engine augmenter 32is shown in greater detail. As shown therein, each of the core engineinjectors 34 includes a spraybar bundle which consists of a plurality oftubes or spraybars 40, 42 and 44 adapted to spray fuel into the coreengine exhaust passageway, which is generally designated by the numeral46. For this reason, one or more holes 48 are spaced along the length ofthe tubes 40, 42 and 44. As is known in the art, the tubes are partiallysurrounded by a fairing 50 which provides a generally airfoil-shapedcontour to the injec-. tor 34 and acts to reduce aerodynamic losseswhich might otherwise be associated with the injector 34.

Similarly, referring to FIG. 4, the fan injectors 36 include a spraybarbundle consisting of a plurality of tubes or spraybars 52, 54 and 56each of which is provided with a plurality of holes 58 for injectingfuel into the fan flow path 22. The injector 36 is also partiallysurrounded by a fairing 60 to reduce aerodynamic losses. As will beapparent from a comparison of the core injector 34 with the fan injector36, the primary difference between the two lies in the fact that the faninjector 36 is angled such that it extends upstream when installedwithin the fan flow path 22. In contrast with this, the core injectors34 lie in a single radial plane. The fan injectors 36 are angled asshown in order to provide greater dwell time for fuel injected from theholes 58 prior to the time of its ignition downstream. This is necessarybecause of the relatively low temperatures associated with the airflowing through the fan flow path 22 as opposed to the highertemperatures of the air flowing through the core engine exhaust 46.These higher temperatures are sufficient to vaporize the flow from theholes 48 in a relatively short distance.

The core injectors 34 and the fan injectors 36 alternate around thecircumference of the gas turbine engine 10. That is, a single coreinjector 34 is positioned between each pair of the fan injectors 36, andthe injectors 34 and 36 are substantially equally spaced around thecircumference of the engine 10.

As further shown in FIGS. 2 and 4, the core injectors 34 and the faninjectors 36 extend through openings 62 provided in the fan casing 18.In order to prevent the escape of hot gas from the fan flow path 22,each of the openings 62 is provided with a seal and damper assembly 64,the details of which are shown in the enlarged sectional view of FIG. 5.As shown therein, the seal and damper assembly 64 consists of a metalcollar 66, which surrounds and captures therein a bushing 68 and a seal70. The collar 66 is mounted directly to the casing 18 in any suitablemanner, such as by means of bolts which extend through bolt holes 72.

As shown in FIGS. 2 and 4, a slightly enlarged boss 74 associated withboth the core injectors 34 and the fan injectors 36 fits within, and isfree to slide radially with respect to, the bushing 68 and the seal 70.The bushing 68 and the collar 66 provide both coulomb damping and axialsupport for the injectors 34 and 36 and support them effectively assimple beams. The seal 70 fits tightly enough around the boss 74 toprevent leakage of air from the engine and to provide viscoelasticdamping in the event of vibration excitation of the fuel system. The fitis, however, not tight enough to restrict the relative therrnalexpansion of the casing 18 and the injectors 34 and 36. When applied toa turbofan engine as shown in FIG. 1, the bushing 68 and the seal aresubjected to relatively low fan air temperatures and may therefore bemade of elastomeric or polymeric materials for lightweight, low cost andminimum leakage operation. Metal bushing and seals of the ring typecould be used to apply this same type of fuel injection system to highertemperature applications, such as straight turbojets.

In order to precisely control the amount of fuel delivered by the coreinjectors 34 and the fan injectors 36, each core injector is suppliedwith a metering valve housing for a metering valve 76 and each faninjector is supplied with a metering valve housing for a metering valve77, the internal details of which valves form no part of the presentinvention. Suffice it to say that the valves 76 and 77 accuratelycontrol the amount of fuel delivered to each of the different tubesassociated with the injectors 34 and 36. For example, each of the valves76 and 77 initially acts to supply lightoff fuel to the spraybar tubes44 and 56 and thereafter to supply sufficient fuel to their respectivespraybar tubes 40 and 57 to accomplish primary operation of theaugmenter 32.

, When higher thrust output is desired from the augmenter 32, themetering valves 76 and 77 act to deliver additional fuel to the tubes 42and 54.

As shown in FIGS. 2 through 4, each of the injectors 34 and 36 isrigidly bolted to a continuous ring-type manifold 78 which includes afan fuel pipe 80, a core fuel pipe 82, and a plurality of injectorconnection pads 84. A gasket 86 of'conventional type is used at thejoint between each of the connection pads 84 and an injector mountingpad 88 associated with each of the housings for metering valves 76 and77. The mounting pads 88 are rigidly connected to the connection pads 84by means of a plurality of bolts 90 and nuts 92.

The joint formed by the connection pads 84 and the mounting pads 88serves as the hydraulic connection between the injectors 34 and 36 andthe fuel manifold 78. In addition, this joint serves to support theinjector radially. It is this feature which permits the elimination ofthe conventional pigtail connection discussed in the introduction above.Since the injectors 34 and 36 are supported radially only by themanifold 78, as opposed to the conventional rigid duct mounting, noflexible pigtail connections are needed to accommodate the relativethermal expansion between the manifold 78 and the fan casing 18 and theseal and damper assembly 64 which is bolted thereto. That is, theinjectors 34 and 36 are fixed radially by the manifold 78 and axially bythe seal and damper assembly 64, while being free to slide radiallywithin the seal and damper assembly 64 to accommodate any thermal growthdifferences. The elimination of the pigtail-type injector connection notonly improves the augmenter envelope but also reduces the weight andimproves maintainability. That is, as should be readily apparent, eachof the injectors 34 and 36 may be replaced solely by disconnecting thebolts and nuts 90 and 92, removing the used injector 34 or 36, slidingin a replacement injector, and replacing the bolts and nuts 90 and 92.

Fuel is delivered to the fuel manifold 78 by means of a fan fuel inlet94 and a core fuel inlet 96. That is, fan fuel is delivered to the pipe80 by means of the inlet 94 and core fuel is delivered to the pipe 82 bymeans of the inlet 96. Fuel is delivered to the core injectors 34 fromthe pipe 82 through a plurality of connecting tubes 98, one of whichextends from the pipe 82 to each of the core injectors 34. Each of thetubes 98 has a passage 99 therethrough which acts to deliver fuel fromthe pipe 82 to the metering valve 76, which controls the amountdelivered to the injector 34. Likewise, fan connecting tubes 100 liebetween the fuel pipe 80 and each of the fan injectors 36 and act todeliver fuel via a passageway 101 to the metering valve 77, whichcontrols the amount delivered to the injector 36.

The fuel manifold 78, and its associated pipes 80 and 82, may be mountedto the engine casing 18 in any suitable manner. For example, as shown inFIG. 6, the pipes 80 and 82 may be mounted to the casing 18 by means ofpivotal links 102 a first end of which is mounted for pivotal movementto a pivot trunnion 104, which is in turn bolted to the fan casing 18.The opposite end of the link 102 is pivotally mounted to saddle 106which is brazed or connected to the pipe 80 in any suitable manner. Thelinks 102 are spaced around the circumference of the casing 18 asrequired. The pipe 82 could be mounted directly tothe casing 18 by usingsimilar links or could be mounted directly to the pipe 80.

In many applications, the pivotal links 102 may not be necessary and thepipes and 82 could be mounted directly to the engine casing 18 as shownin FIG. 7. In this case, the pipe 80 is brazed or welded directly to asaddle 108 which bolts to the casing 18. The pipe 82 is then mounteddirectly to the pipe 80 by means of a plurality of mounting blocks 110,which may also serve as the mounting pads for the injectors 34 and 36.In such a case, the block 1 10 would include a pad face 1 l I having aplurality of holes 112 therein to mate with similar holes in themounting pad 88 of the injectors 34 and 36. Passageways 114 would thenextend from the pipe 82 to each of the core injectors 34, while similarpassageways (not shown) would extend between the pipe 80 and each of thefan injectors 36.

An alternative embodiment of the inventive augmenter fuel injector isshown in FIGS. 8 and 9. The injector assembly shown therein is similarto that described above and utilizes a fuel manifold mounting system asshown in FIG. 7. The primary difference between the systems lies in thefact that a core injector 116 is provided with five spraybar tubes 118,120, 122, 124 and 126. The tubes 118 and 120 are auxiliary fan spraybartubes which extend only through the length of the fan duct flow path 22and terminate at a boss 128 which fits within an opening 130 formed inthe core casing 20. The tubes 122, 124 and 126 extend into the coreengine exhaust passage 46 and perform identical functions to those ofthe tubes 40, 42 and 44 shown in FIGS. 2 and 3. That is, the tube 126delivers a lightoff spray while the tubes 122 and 124 deliver primaryand secondary augmenter fuel to the core exhaust stream.

The tubes 118 and 120 are utilized to provide more uniform distributionof augmenter fuel in the fan flow path 22 by doubling the number of fuelinjector points located within the flow path 22. In order to provide asimple and reliable system while eliminating the need for additionalcostly flow metering valves, the system shown in FIGS. 8 and 9 uses eachof the metering valves 77 associated with each of the fan injectors 36to control the amount of fuel delivered to not only the fan injectors 36but also to the auxiliary fan spraybar tubes 118 and 120. For thisreason, and as shown most clearly in FIG. 9, the fuel injector system isprovided with a plurality of U-shaped tubes 132, which interconnect eachadjoining pair of mounting blocks 110. A passageway 133 is formed withinan enlarged boss portion 134 of the fan injectors 36 to provide aportion of the fuel delivered by the fan metering valves 77 directly tothe auxiliary fan tubes 118 and 120 of the core injector 116 via apassage 135 drilled in a boss 136 of each of the core injectors 34.Thus, when fan duct burning is desired, an operating signal actuates afuel control which delivers fuel to the fan pipe 80. The fan injectormetering valves 77 then operate to deliver the desired amount of fuelfrom the pipe 80 to the fan injectors 36. A portion of this fuel exitsthe fan metering valve 77 via the passage 133 and is bypassed via thetubes 132 and passage 135 to the auxiliary injector tubes 118 and 120 ofthe core injector 116. Thus, the total amount of fan fuel flow ismetered by the same number of metering valves 77 but the number ofinjection points is double because the tubes 118 and 120 also act as faninjectors. As an example, if the gas turbine engine 10 is equipped with28 fan fuel injectors 36 and 28 core fuel injectors 116, the fan ductburning can be accomplished utilizing all 56 injectors whereas the coreduct burning will be accomplished using only the 28 core injectors.

Referring now to FIGS. 10 and 11, another alternative embodiment of theinventive augmenter injector assembly is shown wherein twin injectorsare provided with a single set of metering valves to service twoinjection stations. In this manner, the overall cost and weight of theinjector assembly may be reduced. As shown in FIGS. 10 and 11, theinjector assembly consists of twin spraybar bundles 140 and 142, amanifold connection flange 144, and support bosses 146 and 148. Theinjector assembly is rigidly bolted to a continuous ring-type manifold150, which consists of fan and core fuel pipes 152 and 154,respectively, and a plurality of injector connection pads 156. A gasket158 of conventional design is used between each of the injectorconnection pads 156 and the manifold connection flanges 144. As in theprevious case, this joint provides the hydraulic connection between thespraybar bundles 140 and 142 and the fuel manifold fan and core pipes152 and 154.

In addition, this joint serves to support the injector assembly in theradial direction. Since the injectors are supported radially only by themanifold 150 as opposed to the conventional rigid duct mounting, noflexible pigtail connections are needed to accommodate the relativethermal expansion of the manifold 150 and the fan casing 18 as theirrespective temperatures vary during engine operation. Thermal expansionis accommodated by allowing the injectors to move radially with respectto the fan casing 18 and the seal and damper assembly 64 which ismounted directly to the casing 18 by means of the bolts 160. Theinjector bosses 146 and 148 are free to slide radially with respect tothe bushing 68 and the seal 70 of the seal and damper assembly 64. Onceagain, the bushing 68 and the collar 66 provide axial support for thespraybar bundles 140 and 142.

As further shown in FIG. 11, each of the injector assemblies hasassociated therewith a fan metering valve 162 and a core metering valve164. In contrast with the systems described above, in connection withFIGS. 1 9, each of the spraybar bundles 140 and 142 has associatedtherewith one or more fan injector tubes 166 and one or more coreinjector tubes 168. The fan injector tubes 166 and the core injectortubes 168 extend parallel to each other to form the spraybar bundles 140and 142. The fan injector tubes 166 extend only through the width of thefan flow path 22 and terminate e at a boss 170 which fits within anopening 172 formed within the core engine duct 20.

In operation, fuel is supplied by the manifold 150, and in particular bythe fan and core fuel pipes 152 and 154, respectively, to the fanmetering valve 162 and the core metering valve 164, respectively. Thefan metering valve 162 controls the exact amount of fuel which isdelivered to the fan injector tubes 166, while the core metering valve164 controls the amount of fuel delivered to the core injector tubes168. The fuel injected into the fan flow path 22 or the core exhaustflow path 46 is then ignited by means of suitable igniters (not shown)and the resultant high energy gas stream exits through a propulsivenozzle to provide added thrust to the gas turbine engine.

As described above in connection with a number of preferred embodiments,Applicant has provided a unique augmenter fuel injection system whichhas a number of basic advantages. For example, the mounting systemeliminates the need for pigtail-type injector connections and therebyimproves the envelope of the injection system. A significant reductionin weight is also associated with the elimination of the pigtail-typeconnection. Furthermore, maintainability of the gas turbine engine issignificantly improved in that each of the individual fuel injectors or,in the embodiment of FIGS. 10 and 11, each pair of fuel injectors isreadily removable by merely disconnecting a pair of bolts associatedwith the injector connection pads. A new injector may then be positionedwithin the seal and damper assembly and the bolted connection simplyremade. While a number of preferred embodiments have been described,those skilled in the art will realize that certain changes in theseembodiments may be made without departing from the broader inventiveconcepts taught by Applicant. It is intended, therefore, that theappended claims cover all such modifications and variations which fallwithin the broader inventive concepts.

What I claim is:

1. In a gas turbine engine of the type including a casing which definesan exhaust duct which has an augmenter combustion system located thereinand has a fuel manifold assembly surrounding said duct, the improvementcomprising:

a fuel injection spraybar assembly consisting of a metering valvehousing, at least one spraybar tube extending from said housing radiallyinwardly through said duct, said tube having a fuel passage therethroughand means for spraying fuel therefrom, valve means located within saidhousing for metering fuel delivered to said spraybar tube, and saidvalve housing including a mounting pad adapted to be connected directlyto the fuel manifold assembly and to support said spraybar assemblyalong a first axis substantially perpendicular to the casing, saidmounting pad being offset from a plane in which said spraybar tube liesso as to permit removal of said spraybar tube from said fuel manifoldassembly without the necessity of moving the fuel manifold assembly.

2. The spraybar assembly recited in claim 1 further characterized inthat a plurality of spraybar tubes extend from said valve housing andsaid valve housing includes an enlarged boss portion through which saidspraybar tubes extend.

3. The spraybar assembly recited in claim 2 further characterized inthat said mounting pad provides the hydraulic connection between saidspraybar assembly and the fuel manifold assembly.

4. The spraybar assembly recited in claim 3 in combination with a sealand damper assembly which surrounds said enlarged boss portion, saidseal and damper assembly supporting said spraybar assembly in adirection substantially perpendicular to said first axis whilepermitting relative motion between said spraybar assembly and said sealand damper assembly along said first axis.

5. The combination recited in claim 4 wherein said seal. and damperassembly includes a metal collar adapted to mount to the engine casing,said collar having an opening therethrough adapted to receive saidenlarged boss portion of said spraybar assembly.

6. The combination recited in claim further characterized in that saidmetal collar includes means for providing friction damping of saidspraybar assembly, said friction damping means being sized so as topermit relative thermal expansion of said spraybar assembly and saidcollar.

7. The combination recited in claim 6 wherein said metal collar furtherincludes means for providing a gas seal between said enlarged bossportion and the engine casing, said sealingmeans also providingviscoelastic damping of said spraybar assembly.

8. In a gas turbine engine of the type which includes an engine casingdefining an annular flow path, a compressor, a combustion system, aturbine for driving the compressor, an exhaust system, and an augmentercombustion system for increasing the energy level of the exhaust gasflow prior to its exiting through the exhaust system, the improvementcomprising:

a fuel distribution system for the augmenter including a fuel manifold,a plurality of metering valve housings, valve means located within saidhousing for metering fuel delivered to said spraybar tube, and each ofsaid housings including a mounting pad adapted to be connected directlyto said fuel manifold, each said valve housing having associatedtherewith at least one spraybar tube bundle adapted to extend throughsaid engine casing into the exhaust gas flow path and to deliver fuelthereto, characterized in that said mounting pad acts as the hydraulicfluid connection between said fuel manifold and said spraybar tubebundle and said fuel manifold supports said spraybar assembly in theradial direction, said mounting pad being offset from a plane in whichsaid spraybar tube lies so as to permit removal of said spraybar tubefrom said fuel manifold assembly without the necessity of moving thefuel manifold assembly.

9. The improved fuel distribution system recited in claim 8 wherein eachspraybar bundle includes an enlarged boss section adapted to fit withinan opening in the engine casing and said fuel distribution systemfurther includes a seal and damper assembly associated with eachspraybar bundle, said seal and damper assembly surrounding said bossportion and supporting said spraybar bundle in the axial direction.

10. The improved fuel distribution system recited in claim 9 whereinsaid seal and damper assembly includes a collar adapted to be connecteddirectly to the engine casing and said collar includes a gas seal forminimizing the flow of fluid between said collar and said spraybarbundle.

11. The improved fuel distribution system recited in claim 10 whereinsaid collar also includes bushing means for friction damping the fueldistribution system in the event of vibration excitation of said system.

12. The improved fuel distribution system recited in claim 11 whereinsaid friction damping is provided by an elastomeric bushing whichsurrounds said boss portion of said spraybar bundle, and said gas sealprovides viscoelastic damping in the event of vibration excitation ofsaid system.

13. The improved fuel distribution system recited in claim 12 whereinsaid fuel manifold includes separate fan and core fuel pipes and meansfor connecting a first plurality of said metering valve housings to saidfan fuel pipe and the remaining metering valve housings to said corefuel pipe.

14. The improved fuel distribution system recited in claim 12 furthercharacterized in that each of said metering valve housings hasassociated therewith at least two of said spraybar bundles and each saidmetering valve housing provides fuel from said fan fuel pipe to fanspraybar tubes associated with each said bundle and fuel from said corefuel pipe to core spraybar tubes associated with each said bundle.

15. A gas turbine engine including a casing defining a flow path, acompressor, a primary combustion system, a turbine for driving saidcompressor, an exhaust nozzle, and an augmenter combustion system, saidaugmenter system including a fuel distribution system which includes afuel manifold, a plurality of metering valve housings, valve meanslocated within said housing for metering fuel delivered to said spraybartube, and each of said housings including a mounting pad adapted to beconnected directly to said fuel manifold, each said valve housing havingassociated therewith at least one spraybar tube bundle adapted to extendthrough said engine easing into the exhaust gas flow path and to deliverfuel thereto, characterized in that said mounting pad acts as thehydraulic fluid connection between said fuel manifold and said spraybartube bundle and said fuel manifold supports said spraybar assembly inthe. radial direction, said mounting pad being offset from a plane inwhich said spraybar tube lies so as to permit removal of said spraybartube from said fuel manifold assembly without the necessity of movingthe fuel manifold assembly, each said spraybar bundle including anenlarged boss section adapted to fit within an opening in said casing,and a seal and damper assembly associated with each said spraybarbundle, said seal and damper assembly including means for mounting saidassembly to said casing, means for supporting said bundle in the axialdirection, and means for damping vibration of said bundle.

1. In a gas turbine engine of the type including a casing which definesan exhaust duct which has an augmenter combustion system located thereinand has a fuel manifold assembly surrounding said duct, the improvementcomprising: a fuel injection spraybar assembly consisting of a meteringvalve housing, at least one spraybar tube extending from said housingradially inwardly through said duct, said tube having a fuel passagetherethrough and means for spraying fuel therefrom, valve means locatedwithin said housing for metering fuel delivered to said spraybar tube,and said valve housing including a mounting pad adapted to be connecteddirectly to the fuel manifold assembly and to support said spraybarassembly along a first axis substantially perpendicular to the casing,said mounting pad being offset from a plane in which said spraybar tubelies so as to permit removal of said spraybar tube from said fuelmanifold assembly without the necessity of moving the fuel manifoldassembly.
 2. The spraybar assembly recited in claim 1 furthercharacterized in that a plurality of spraybar tubes extend from saidvalve housing and said valve housing includes an enlarged boss portionthrough which said spraybar tubes extend.
 3. The spraybar assemblyrecited in claim 2 further characterized in that said mounting padprovides the hydraulic connection between said spraybar assembly and thefuel manifold assembly.
 4. The spraybar assembly recited in claim 3 incombination with a seal and damper assembly which surrounds saidenlarged boss portion, said seal and damper assembly supporting saidspraybar assembly in a direction substantially perpendicular to saidfirst axis while permitting relative motion between said spraybarassembly and said seal and damper assembly along said first axis.
 5. Thecombination recited in claim 4 wherein said seal and damper assemblyincludes a metal collar adapted to mount to the engine casing, saidcollar having an opening therethrough adapted to receive said enlargedboss portion of said spraybar assembly.
 6. The combination recited inclaim 5 further characterized in that said metal collar includes meansfor providing friction damping of said spraybar assembly, said frictiondamping means being sized so as to permit relative thermal expansion ofsaid spraybar assembly and said collar.
 7. The combination recited inclaim 6 wherein said metal collar further includes means for providing agas seal between said enlarged boss portion and the engine casing, saidsealing means also providing viscoelastic damping of said spraybarassembly.
 8. In a gas turbine engine of the type which includes anengine casing defining an annular flow path, a compressor, a combustionsystem, a turbine for driving the compressor, an exhaust system, and anaugmenter combustion system for increasing the energy level of theexhaust gas flow prior to its exiting through the exhaust system, theimprovement comprising: a fuel distribution system for the augmenterincluding a fuel manifold, a plurality of metering valve housings, valvemeans located within said housing for metering fuel delivered to saidspraybar tube, and each of said housings including a mounting padadapted to be connected directly to said fuel manifold, each said valvehousing having associated therewith at least one spraybar tube bundleadapted to extend through said engine casing into the exhaust gas flowpath and to deliver fuel thereto, characterized in that said mountingpad acts as the hydraulic fluid connection between said fuel manifoldand said spraybar tube bundle and said fuel manifold supports saidspraybar assembly in the radial direction, said mounting pad beingoffset from a plane in which said spraybar tube lies so as to permitremoval of said spraybar tube from said fuel manifold assembly withoutthe necessity of moving the fuel manifold assembly.
 9. The improved fueldistribution system recited in claim 8 wherein each spraybar bundleincludes an enlarged boss section adapted to fit within an opening inthe engine casing and said fuel distribution system further includes aseal and damper assembly associated with each spraybar bundle, said sealand damper assembly surrounding said boss portion and supporting saidspraybar bundle in the axial direction.
 10. The improved fueldistribution system recited in claim 9 wherein said seal and damperassembly includes a collar adapted to be connected directly to theengine casing and said collar includes a gas seal for minimizing theflow of fluid between said collar and said spraybar bundle.
 11. Theimproved fuel distribution system recited in claim 10 wherein saidcollar also includes bushing means for friction damping the fueldistribution system in the event of vibration excitation of said system.12. The improved fuel distribution system recited in claim 11 whereinsaid friction damping is provided by an elastomeric bushing whichsurrounds said boss portion of said spraybar bundle, and said gas sealprovides viscoelastic damping in the event of vibration excitation ofsaid system.
 13. The improved fuel distribution system recited in claim12 wherein said fuel manifold includes separate fan and core fuel pipesand means for connecting a first plurality of said metering valvEhousings to said fan fuel pipe and the remaining metering valve housingsto said core fuel pipe.
 14. The improved fuel distribution systemrecited in claim 12 further characterized in that each of said meteringvalve housings has associated therewith at least two of said spraybarbundles and each said metering valve housing provides fuel from said fanfuel pipe to fan spraybar tubes associated with each said bundle andfuel from said core fuel pipe to core spraybar tubes associated witheach said bundle.
 15. A gas turbine engine including a casing defining aflow path, a compressor, a primary combustion system, a turbine fordriving said compressor, an exhaust nozzle, and an augmenter combustionsystem, said augmenter system including a fuel distribution system whichincludes a fuel manifold, a plurality of metering valve housings, valvemeans located within said housing for metering fuel delivered to saidspraybar tube, and each of said housings including a mounting padadapted to be connected directly to said fuel manifold, each said valvehousing having associated therewith at least one spraybar tube bundleadapted to extend through said engine casing into the exhaust gas flowpath and to deliver fuel thereto, characterized in that said mountingpad acts as the hydraulic fluid connection between said fuel manifoldand said spraybar tube bundle and said fuel manifold supports saidspraybar assembly in the radial direction, said mounting pad beingoffset from a plane in which said spraybar tube lies so as to permitremoval of said spraybar tube from said fuel manifold assembly withoutthe necessity of moving the fuel manifold assembly, each said spraybarbundle including an enlarged boss section adapted to fit within anopening in said casing, and a seal and damper assembly associated witheach said spraybar bundle, said seal and damper assembly including meansfor mounting said assembly to said casing, means for supporting saidbundle in the axial direction, and means for damping vibration of saidbundle.